Internal combustion engine



April 21, 1959 w. w. FRIEDRICH INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 1 Iioi W////0/77 W F/veo r/cfi INVENTOR.

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ATTORNEY April 21, 1959 8w, w. FRIEDRICH INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 2 Filed May 10, 1957 W////am W Fr/eo r/cfi INVENTOR.

BY 8 aw; W

Q ATTORNEY United States Patent This invention relates to an internal combustion engine and more particularly to an engine of the opposed piston type having means for coordinating the movement of the pistons whereby improved operating characteristics are attained.

This application is a continuation-in-part of a prior application filed by the same applicant on August 1, 1956, under Serial No. 601,397, now Patent No. 2,821,968, issued February 4, 1958.

The invention has for an important object the provision of an internal combustion engine of the type having opposed pistons disposed in the same cylinder which are arranged for movement in opposite directions and embodying means for connecting the pistons in driving relation to a driver shaft in a manner to cause the force exerted during a power stroke of either of the pistons to be exerted at a point substantially past dead center, whereby starting of the engine is facilitated.

Another object of the invention is to provide an engine of the kind referred to wherein one of the opposed pistons is of an outer piston sleeve-like construction within which a third or inner piston is movably disposed and wherein means is embodied for causing the inner piston to perform a compression stroke during a power stroke of the sleevelike piston.

A further object of the invention is the provision of an internal combustion engine having opposed pistons and wherein one of the opposed pistons is an outer or sleevelike piston within which a third or inner piston is movably disposed and wherein the force exerted at the beginning of a power stroke of the inner piston takes place when the outer end of the piston rod of the inner piston is substantially disposed from the dead center position of said outer end, whereby the leverage of said power stroke is greatly increased.

A still further object of the invention is to provide an internal combustion engine of the two-cycle type having opposed pistons movably disposed in a single cylinder which are arranged to move different distances during a power stroke and also having means for connecting the pistons in driving relation to a drive shaft to cause the shaft to be rotated by the movement of the pistons.

The above and other important objects and advantages of the invention may best be understood from the following detailed description, constituting a specification of the same, when considered in conjunction with the annexed drawings, wherein Figure 1 is a side elevational view, partly in cross-section, illustrating a preferred embodiment of the invention, showing the opposed pistons in a carrying over position and a third or inner piston in firing position;

Figure 2 is a view similar to that of Figure 1, showing the opposed pistons in firing position and the third or inner piston in its intake and exhaust position;

Figure 3 is a view similar to that of Figure 1, showing the opposed pistons in the exhaust or intake position and the third or inner piston in compression position;

Figure 4 is a view similar to that of Figure 1, showing the opposed pistons in compression position and the the third or inner piston in carrying over position;

Figure 5 is an end elevational view, partly in crosssection, of the invention as illustrated in Figure 2; and

Figure 6 is a view similar to that of Figure 5, showing the invention as illustrated in Figure 3.

Referring now to the drawings in greater detail, the engine of the invention has a cylinder block 10 provided with a bore 12 forming a cylinder of the engine, it being understood that the block may be constructed in the usual manner with conventional cooling means, such as water passages or dissipating fins, not shown. The cylinder block may be furnished with hollow enlargements 14 and 16, respectively, at its opposite ends, within which a crankshaft mechanism may be located.

Within the bore 12 opposed pistons 18 and 20 are movably disposed for movement toward and away from each other, the piston 18 being of sleeve-like formation connected by relatively short piston rods 22 to small gears 24, mounted in opposite, laterally aligned bearings 26, carried by the enlargement 14 of the engine block 10, and the piston 20 being similarly connected by a relatively long piston rod 28 to a crankshaft 30, rotatably mounted in opposite, laterally aligned bearings 32 carried by the enlargement 16 of the engine block.

An inner piston 52 is provided within the sleeve-like piston 18, which inner piston is connected by a relatively long connecting rod 54 to a crankshaft 56, journalled in bearing 58 in the wall of the enlargement 14 and which carries large gears 60 rotatable with the crankshaft and in intermeshing engagement with the gears 24. The diameter of the gears 60 is twice the diameter of the gears 24.

The crankshaft 56 extends through the wall of the engine block and outwardly and beyond, and carries one or more bevel gears 34 exteriorly of the engine block, and the crankshaft 30 is similarly extended and carries one or more bevel gears 36, having the same diameter as that of the gears 34. Means is provided for causing the gears 34 and 36 to rotate simultaneously, which means may take the form of shafts 38, suitably mounted, for rotation, and which are provided with bevel gears 40 positioned in meshing engagement with the gears 34 and bevel gears 32 which are positioned in meshing engagement with the gears 36.

The engine block has an exhaust port 44 and an inlet port 46, which ports are suitably located to allow a supply of fuel to be introduced into bore 12 between the pistons 18 and 20 and to exhaust products of combustion therefrom when the pistons 18 and 20 are in inlet and exhaust position, as illustrated in Figure 3. Suitable means, such as a spark plug, indicated at 48, is provided in the engine block, which is connected into an ignition system of conventional type, not shown, in a manner to cause ignition of the fuel in the bore between the opposed pistons 18 and 20, when the pistons are in firing position as seen in Figure 5.

The arrangement of the pistons is such that when the piston rods 22 are in positions parallel to the axis of piston 18 the piston rod 28 of the piston 20 will be out of axial alignment with the piston 20. As seen in Figure 2 when the pistons 18 and 20 are in firing position the piston rods 22 are in their innermost position in the bore 12 and in vertical alignment with the axis of the piston 18, the crank of the crankshaft 56 being then nearly in its upmost position and the lower end of the piston rod 28 of piston 20 will be in a position approximately to the right of vertical. When firing takes place the lower end of the connecting rod 28 is in an oft-center position, and because of the driving connection between the gears 34 and 36 the piston 18 will be moved outwardly at the same time as piston 20. By this arrangement improved operation of the engine is obtained, the gears 24 being rotated V2 turn to the position shown in Figure 3, while the crankshaft 30 is rotated A; turn to the position shown in Figure 3. Upon the movement of the pistons toward each other, from the position of Figure 3 to that of Figure 4, the gears 24 will again be rotated /2 turn, while the crankshaft 30 is rotated a further A turn.

The piston 20 may be provided with the usual baflle 50, to intercept the inflow of fuel through the port 46, to prevent the fuel from flowing out of the exhaust port 44 during the intake and exhaust part of the two-cycle operation of the engine.

The inner piston 52 has a connecting rod 54 which is connected at its outer end to the crankshaft S6, rotatably mounted in aligned, laterally spaced bearings 58 carried by the enlargement 14 of the engine block and upon which the large gears 60 are mounted to rotate with the crankshaft.

The piston 20 has a connecting rod 28 which is connected at its outer end to a crankshaft 30, rotatably mounted in aligned, laterally spaced bearings 32 carried in the enlargement 16, in crankshaft 30 extending outwardly upon the enlargement, and carrying gears 36; exteriorly of the enlargement.

The engine block has also an exhaust port 66 and an intake port 68, and the sleeve-like piston 18 has ports 70 and 72 positioned to be in communication with the exhaust port 66 and intake port 68 and with the interior of the sleeve-like piston when the sleeve-like piston and the inner piston 52 are in intake and exhaust position, as

shown in Figure 2. A bafile 74 is provided on the inner piston 52, which is positioned in the path of inflow of fuel through the intake port 68 and port 72 when the inner piston and sleeve-like piston are in the intake and exhaust position shown in Figure 2, to intercept the inflow of fuel to prevent the fuel from flowing out through the exhaust ports 70 and 66.

In the operation of the engine firing takes place between the pistons 18 and 20 in the position shown in Figure 2, wherein the lower end of the connecting rod 28 is out of vertical alignment with the piston 20 and because of the driving connection between the gears 36 and 34 the sleeve-like piston 18 will move outwardly at the same time that the piston 20 moves outwardly. By this arrangement the mechanical advantage of the full length of the lever arm of the crankshaft 30 is obtained at the time of firing and the full force of the explosion on the pistons 18 and 20 is utilized.

At the time of firing of the compressed fuel between the pistons 18 and 20 the inner piston 52 is substantially in its outermost position relative to the sleeve-like piston 18, and the pistons 52 and 18 are in the intake and exhaust position, as illustrated in Figure 2. When firing has taken place between the pistons 18 and 20 and these pistons move to the exhaust and intake position shown in Figure 3 the fuel between the sleeve-like piston 18 and the inner piston 52 is compressed.

Upon firing of the fuel which is compressed between the inner piston 52 and sleeve-like piston 18, as seen in Figure 1, the outer end of connecting rod 54 of inner piston 52 will be out of vertical alignment with the pistons, and that the full mechanical advantage of the length of the lever arm of the crankshaft 56 is obtained,

and due to the inner meshing engagement of the gears 60 and 24, the sleeve-like piston 18 moves away from the inner piston 52 as the inner piston 52 moves outwardly.

Upon rotation of the crankshaft 56 A turn the gears 24 will be rotated /2 turn and the crankshaft 30' will also be rotated turn.

It will be apparent that the arrangement of the pistons is such that all of the pistons are connected in driving relation, whereby the rotative forces exerted by the pistons on the crankshafts are applied in a manner to secure 4 maximum mechanical advantage and smoothness of operation.

Means is provided, such as a spark plug 76, in the engine block, at a location to be in registration with an opening 78 through the wall of the sleeve-like piston. When the sleeve-like piston and the inner piston are in firing position.

It will thus be seen that the invention, constructed and arranged as described above provides an internal combustion engine of the two-cycle type, by which improved smoothness and efiiciency of operation is obtained.

The invention has been described herein in connection with certain specific embodiments of the same, but it will be understood that this is intended by way of illustration only, and that various changes can be made in the construction and arrangement of the parts within the spirit of the invention and the scope of the appended claims.

Having thus clearly described and shown the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In an internal combustion engine, a cylinder, opposed pistons movably disposed in the cylinder and forming therewith a combustion chamber between the pistons, one of said opposed pistons being of sleeve-like formation having a closed end, an inner piston movably disposed in the sleeve-like piston and forming therewith an inner combustion chamber, a large gear connected to the inner piston to be rotated thereby, a small gear connected to the sleeve-like piston to be rotated thereby and in intermeshing engagement with said large gear, a small gear connected to the other of said opposed pistons to be rotated thereby, said large gear being of a size to rotate once during two rotations of said small gears and means forming a driving connection between said large gears and the small gear of said one of the said opposed pistons to cause said small gears to rotate simultaneously.

2. In an internal combustion engine, a cylinder, opposed pistons movably disposed in the cylinder and forming therewith a combustion chamber between the pistons, one of said opposed pistons being of sleeve-like formation, an inner piston movably disposed in the sleevelike piston and forming therewith an inner combustion chamber, a large gear connected to the inner piston to be rotated thereby, a small gear connected to the sleeve-like piston to be rotated thereby and in meshing engagement with said large gear, a small gear connected to the other of said opposed pistons to be rotated thereby, said large gear being of a size to rotate once during two rotations of said small gears, means forming a driving connection between said large gear and said small gear of said other of said opposed pistons to cause said small gears to rotate simultaneously, the inner piston being connected to the large gear of the inner piston at a point ninety degrees in advance of the point of connection of the other of said opposed pistons to the small gear of said other of said opposed pistons.

3. In an internal combustion engine, a cylinder, opposed pistons movably disposed in the cylinder and fonning therewith a first combustion chamber between the pistons, one of said opposed pistons being of sleeve-like formation, an inner piston movably disposed in the sleevelike piston and forming therewith a second combustion chamber, a large gear for said inner piston and a small gear for the other of said opposed pistons, a small gear for said sleeve-like piston in intermeshing engagement with the gear for the inner piston, a connecting rod pivotally connected at one end to each piston and whose other end is connected to the gear for that piston to be rotated thereby, means forming a driving connection between the gears of said inner piston and of said other of said opposed pistons :to cause the same to rotate together, the other end of the piston rod of said inner piston being in a position displaced less than ninety degrees from a position in axial alignment with said inner piston at the time of ignition in said second chamber and the 5 other end of the connecting rod of said other of said opposed pistons being displaced ninety degrees from the position of the other end of the connecting rod of said sleeve-like piston at the time of ignition in said first chamber.

References Citedin the file of this patent UNITED STATES PATENTS 1,644,954 Shearer V Oct. 11, 1927 5 2,506,512 Mallory May 2, 1950 

